{"id":28864,"date":"2018-10-08T06:49:57","date_gmt":"2018-10-08T06:49:57","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=28864"},"modified":"2018-10-08T06:53:27","modified_gmt":"2018-10-08T06:53:27","slug":"palu-landslides-3","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/10\/08\/palu-landslides-3\/","title":{"rendered":"The Palu landslides &#8211; the worst landslide disaster in five years?"},"content":{"rendered":"<h4>The Palu landslides &#8211; the worst landslide disaster in five years?<\/h4>\n<p>It is becoming increasingly clear that the lass of life from the three <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2018\/10\/05\/indonesian-earthquake\/\">Palu landslides<\/a>, triggered by the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2018\/10\/03\/palu-landslides-1\/\">earthquake in Sulawesi<\/a>, is very high.\u00a0 In particular, the two landslides that struck main parts of the town, at Balaroa and Petobo, are thought to have exacted a terrible toll.\u00a0 A spokesman from Indonesia&#8217;s disaster agency,\u00a0Sutopo Purwo Nugroho, <a href=\"https:\/\/www.scmp.com\/news\/asia\/southeast-asia\/article\/2167341\/relief-aid-pours-disaster-hit-indonesian-region-week-after\">was quoted thus on Sunday<\/a>:-<\/p>\n<p class=\"v2-processed\"><em>\u201cBased on reports from the (village) heads of Balaroa and Petobo, there are about 5,000 people who have not been found. Nevertheless, officials there are still trying to confirm this and are gathering data. It is not easy to obtain the exact number of those trapped by landslides, or liquefaction, or mud.\u201d<\/em><\/p>\n<p>Given the scale of the Palu landslides, and the very high number of houses involved, this level of loss is entirely possible.\u00a0 It is clear from the videos that the flow was highly mobile, which will have made escape from the crush of houses and debris extremely challenging, especially in a dense network of streets.\u00a0 The mobility of the debris will have meant that buildings will have filled with mud, even where there were voids that might have protected a person.\u00a0 It is therefore unsurprising that no survivors have now been recovered in a week.\u00a0 <a href=\"https:\/\/www.youtube.com\/watch?v=o02CTTDp4s4\">This AFP video shows the magnitude of the damage<\/a>:-<\/p>\n<iframe loading=\"lazy\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/o02CTTDp4s4?feature=oembed\" frameborder=\"0\" allow=\"autoplay; encrypted-media\" allowfullscreen><\/iframe>\n<p>.<\/p>\n<p>The search for the missing will continue until Thursday; after that it is likely that the landslide sites will need to be classified as mass graves.<\/p>\n<p>I suspect that this will be the highest loss in a landslide event since the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2013\/10\/29\/kedarnath-photo-2\/\">2013 Kedarnath debris flow<\/a>. It will be the worst earthquake-induced landslide event since the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2018\/05\/15\/research-legacy-1\/\">2008 Wenchuan earthquake<\/a>.<\/p>\n<p>There is considerable confusion in the reporting as to what actually happened at Balaroa and Petobo.\u00a0 This is Petobo, as seen from the air:-<\/p>\n<div id=\"attachment_28874\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-28874\" class=\"size-full wp-image-28874\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/10\/18_10-Palu-13-e1538978547905.jpeg\" alt=\"Palu landslides\" width=\"640\" height=\"361\" \/><p id=\"caption-attachment-28874\" class=\"wp-caption-text\">The aftermath of one of the Palu landslides, in this case the slide at Petobo. Image from <a href=\"https:\/\/news.detik.com\/berita\/4236878\/petobo-palu-ditelan-lumpur-pascagempa-ratusan-orang-diduga-terkubur\">Detik News<\/a><\/p><\/div>\n<p>.<\/p>\n<p>Whilst this is Balaroa:-<\/p>\n<div id=\"attachment_28878\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-28878\" class=\"size-full wp-image-28878\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/10\/18_10-Palu-14-e1538978848117.jpg\" alt=\"Palu landslides\" width=\"640\" height=\"474\" \/><p id=\"caption-attachment-28878\" class=\"wp-caption-text\">The Palu landslides: the aftermath of the Balaroa landslide. Image via <a href=\"https:\/\/newsinfo.inquirer.net\/1038888\/watch-aerial-footage-shows-houses-in-balaroa-leveled-by-sulawesi-quake\">The Daily Telegraph.<\/a><\/p><\/div>\n<p>.<\/p>\n<p>Various newspaper articles have described these events as being liquefaction,<a href=\"https:\/\/www.scmp.com\/news\/asia\/southeast-asia\/article\/2167341\/relief-aid-pours-disaster-hit-indonesian-region-week-after\"> even nonsense such as<\/a>:<\/p>\n<p class=\"v2-processed\"><em>&#8220;Petobo, a cluster of villages in Palu, was virtually wiped out by the powerful quake and wall of water that devastated Palu.\u00a0 Much of it was sucked whole into the ground as the vibrations from the quake turned soil to quicksand.&#8221;<\/em><\/p>\n<p>In both cases these were landslides, of that there is no doubt.\u00a0 The mechanism of failure might have been liquefaction, but this is just a hypothesis.\u00a0 The houses were not sucked into the ground, they were buried and crushed by a flow of debris coming from upslope, albeit down a very low gradient slope.\u00a0 Whilst this might seem academic, it is important in the context of understanding future hazards.<\/p>\n<p>To understand why these slopes flowed under the effects of earthquake shaking will require detailed investigations, in due course, using field data collection, lab testing and modelling.\u00a0 But <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2013\/07\/26\/spectacular-landslides-from-the-gansu-earthquake-this-week\/\">seismically induced flowslides<\/a> are not a new phenomenon by any means, and in <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2009\/09\/13\/on-the-loss-of-life-in-landslides-during-the-1949-khait-earthquake\/\">previous events they have caused huge numbers of fatalities<\/a>.<\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>The Palu landslides, triggered by the Sulawesi earthquake, may have been the worst mass movement event in terms of loss of life for five years<!-- AddThis Advanced Settings generic via filter on wp_trim_excerpt --><!-- AddThis Share Buttons generic via filter on wp_trim_excerpt --><\/p>\n","protected":false},"author":22,"featured_media":28878,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[537],"tags":[23,469,141,17788,314],"class_list":["post-28864","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earthquake-induced-landslide","tag-earthquake","tag-featured","tag-indonesia","tag-palu","tag-se-asia"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/28864","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=28864"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/28864\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/28878"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=28864"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=28864"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=28864"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}